The present invention concerns a rotating bezel system for a timepiece.
Known rotating bezel systems 2, seen in FIG. 1, comprise a rotating bezel 4 taking the form of an annular part having a top surface and a bottom surface, with the top surface being the part visible to the user. This bezel has a notch 6 on the bottom surface thereof. The rotating bezel system further includes a spring means 8. This spring means 8 is inserted between the rotating bezel and the middle part 3 of timepiece 1, when bezel 4 is forcibly fitted onto the middle part of the timepiece. This spring means 8 takes the form of a flat ring comprising leaves on the surface thereof facing the notch in the bezel. These leaves are arranged to tilt relative to the plane of the flat ring. The leaves have some elasticity so that the spring means acts on the rotating bezel to exert a vertical force. This vertical force has a tendency to push the bezel off the middle part of the timepiece.
Further, the leaves serve to cooperate with the notch in the bottom surface of the bezel. The leaves and notch are thus configured so that the bezel can only rotate in one direction. The leaves prevent the bezel from rotating if the user attempts to rotate said bezel in the wrong direction. Generally, the bezel and the spring means are made of steel which has the advantage of being durable and inexpensive.
The bezel is driven onto the middle part of the watch case. To achieve this, the middle part has a peripheral shoulder in which said rotating bezel system is placed, the vertical wall of said shoulder having a peripheral groove 10. The bezel is an annular part having a peripheral rim on the bottom surface thereof. The rim is provided with a continuous protruding portion 12 extending along said rim towards the axial centre of the bezel. When said rotating bezel system is driven onto the middle part of the watch case, the continuous protruding portion is inserted into the peripheral groove of the shoulder ensuring that the bezel is held vertically on the middle part.
One drawback of this system is that it requires significant force to assemble said rotating bezel system. Indeed, when the bezel is forcibly fitted onto said middle part so that the continuous protruding portion is inserted into the peripheral groove, significant stresses are applied to the bezel. These stresses may, if incorrectly applied, cause deformations of the bezel and thus malfunction of the rotating bezel system.
Moreover, the snap fit assembly of the bezel is permanent. Indeed, it is impossible to remove the rotating bezel system from the middle part afterwards. Attempts to remove said rotating bezel system result in the destruction of said system.